Dry cleaning process and composition



strated.

United States Patent Office 3,335,093 Patented Aug. 8, 1967 3 335 093 DRY CLEANING PROCESS AND COMPOSITION Herman Spencer Gilbert, Angleton, and John Henry Brown, Jr., Lake Jackson, Tex., assignors to The Dow ture, of course, is normally present in materials being cleaned and additional moisture is generally present in the formulated dry cleaning solvent initially introduced into the dry cleaning system.

A series of forty loads of clothes, averaging about u o I o 5 I 52335:: Company Midland Mlch" a corporanon of eight pounds per load, were cleaned in a regular commer- No Drawing. Filed Feb. 8, 1965, Ser. No. 431,205 elal dry ng ma hine employmg a standard peri (CL 252 170 chloroethylene dry cleaning solvent system used in the cleaning industry. A number of new, 4" by 11" swatches The present inv ti n l t t a new process d om. 10 of cotton, wool, viscose tafieta and spun acetate materials position for cleaning textile materials. More specifically, Were cleaned tegethel With the Series Of 40 leads of elethes this invention is concerned with improving the brightness and dePOSIt Q polyvalent mete1 ions thereon Was of dry cleaned materials by inhibiting the deposition of termlned y emlssien P PY- A Portion of each metallic impurities on such materials during a cleaning of the Swatches Was moistened with a e drops of process. 15 ionized water prior to each cleaning cycle to demonstrate It has been discovered that polyvalent metal ions, genthe effect Of moisture, present in the material being erally present in dry cleaning solvent systems, tend to cleaned, on the tendency of the metal ions to deposit on deposit on fibrous materials cleaned therein, Such dethe cloth. The original metal content Of these new swatches posits, it has been found, are responsible for decreasing provides a standard for determination of the amounts the brightness of the cleaned materials. of metal deposited during cleaning. The results are shown In general dry cleaning practiceasolvent system comprisin Table I, below, where metal content is reported as ing essentially a halogenated organic dry cleaning solvent parts per million (p.p.m.), weight of cloth basis.

TABLE I M t 1C 1; t Swatch Description 6 a on en p m) Ca Mg Fe 011 Ti Zn Pb Cd 15 14 20 10 23 Cotton 27 65 30 24 21 22 42 30 20 55 47 340 85 65 7 14 47 2 2 WOOL.-. 1.5 12 220 12 36 6 13 9 6.5 48 13 20 35 3 Viscose Tafieta- 30 12 100 70 15 65 2s 20 50 13 4s 2 20 10 2 Spun Acetat 34 2 20 10 16 70 30 20 10 10 is commonly employed, erg. chlorinated hydrocarbons such as perchloroethylene, trichloroethylene and'the like, and is frequently formulated to contain detergents or soaps and other. additives. The term solvent system is usedherein to designate these comrnonly used solvents and formulated solvents.

In the present invention, deposition of polyvalent metal ions from a solvent system onto fibrous materials being cleaned therein is inhibited by addition of minor amounts of a lower alkanedione or cycloalkanedione to the solvent system employed in the dry cleaning process. It is believed that this dione additive, which is soluble in the solvent system in the amounts used to practice the present invention, reacts with polyvalent metal ions present to polyvalent metal ions onto the material. The tendency of polyvalent metal ions to deposit on materials from the contacting dry cleaning solvent system is also demon- EXAMPLE 1 materials cleaned therein and that such deposits adversely effect the brightness Of the cleaned materials, experiments" were conducted to determine quantitative eflects of this unexpected phenomenon. Investigation revealed that the polyvalent metal ion deposit is in most instances, especially ;mar ked where moisture is present in the material. Moisto wet area deposition with subsequent capillary action.

(similar to paper partition chromatography) depositing a large portion of the wet area metal species in the ring forming the wet-dry interface.

EXAMPLE 2 This experiment illustrates the correlation between reflectance loss and the presence of polyvalent metals in a dry cleaning solvent system used to clean swatches of material. I

A series of cloth swatches was agitated for extended time periods in quantities of three different commercially available dry cleaning solvent systems. In each case the reflectance readings of swatches agitated in samples of the new, uncontaminated dry cleaning solvent system were compared with reflectance readings of swatches agitated in portions of the same dry cleaning solvent system which had been saturated with Zn, Cu, Fe, and Mg ions. These saturated portions were prepared by extended stirring of water soluble salts of these metal species with the dry cleaning solvent employed. The reflectance readings, taken on a standard reflectometer, are tabulated in Table II, below, as taken initially and at the end of one, two and three days of agitation in the solvent. In the following table, Solvent 1 is perchloroethylene; Solvent 2 is a chlori- TABLE II.REFLECTANCE READINGS 1 day 2 days 3 days Spun Acetate Swatches: 1

Solvent 1 Metals absent 84. 5 84. 5 84. 5 Metals present. 84. 82. 81. 5 Solvent 2 Metals absent- 84. 5 84. 0 84. 0 Metals present 83.0 80. 5 78. 5 Solvent 3 Metals absent 83.5 83.0 83.0 Metals present 82. 0 78. 5 78. 5 Worsted Gabardine Wool Swatches: 2

Solvent 1 Metals absent 73. 0 73. 0 73. 0 Metals present 70. 0 68.0 67. 5 Solvent 2 Metals absent. 73. 0 72. 5 73.0 Metals present 71. 5 67. 5 65. 0 Solvent 3 Metals absent 72. 5 72. 5 72. 5 Metals present 71. 0 69.5 69. 5

1 Initial reflectance readings-85 units.

2 Initial reflectance reading-73.5.

As shown by the comparative reflectance readings in Table II, above, the presence of the polyvalent metal ions (which were the only contaminants present in the test samples of solvent) cause a significant loss of whiteness in the swatches.

In practice of the present invention, a quantity of from about 0.1 to 3 parts by weight of a lower alkanedione or a cycloalkanedione is added to 100 parts by weight of a dry cleaning solvent system to form a new composition of the present invention. This new composition is utilized to inhibit the previously described deposition of metallic impurities on fibrous materials during dry cleaning operations. The term lower alkanedione is used herein to designate an alkanedione containing from 1 to 6 carbon atoms, inclusive. The term cycloalkanedione as used herein includes cycloalkanediones having one or more alkyl substituents, which substituents contain from 1 to 4 carbon atoms, inclusive. These new compositions of the present invention may also be employed for purposes, other than usual dry cleaning procedures, where solvent systems are utilized. Examples of such uses include water repellant formulations, spotting agent, moth proofing and static eliminator systems and sizing solutions.

Specific examples of lower alkanediones and cycloalkanediones employed in practice of the present invention include acetylacetone, 2,3-butanedione, 2,4-pen-tanedione, 2,5-hexanedione and 5,5-dimethyl-1,3-cyclohexanedione.

The following examples describe completely representative specific embodiments of the method and compositions of the present invention. These examples, however, are not to be interpreted as limiting the invention other than as defined in the claims.

EXAMPLE 3 A series of four glass containers holding 100 ml. quantities of a fresh solvent system and either cotton or spun acetate cloth samples was prepared. A commercially available solvent system, widely used in coin-operated dry cleaning machines and containing small amounts of a petroleum sulfonate base detergent, was employed. A quantity of analytical reagent grade zinc, magnesium, iron and copper (0.2 gram each) was added to each glass container. A quantity of 1000 parts per million (p.p.m.) of acetylacetone, based on the solvent system, was added to one container holding cotton swatches and one container holding spun acetate swatches. The four containers were then agitated for 90 hours after which the reflectance of the cloth swatches was measured. The cotton swatches EXAMPLE 4 In the manner of the preceding experiment, a quantity of galvanized metal was employed in place of the Zn, Cu, Fe and Mg used above. Table III, below, shows the reflectance readings of cotton swatches, after various time periods, agitated in solvent systems with and without acetylacetone present. The initial reflectance of the cotton swatches, before treatment, was 75 units.

TABLE III Reflectance Reading After- 1 day 3.7 days 6 days 7 days 11 days Acetylacetone absent 69. 6 67.3 67.0 66.5 66.1 Acetylacetone present 68.9 68.8 68.7

While the improvement in reflectance readings is not as marked in this example as in Example 3, it must be noted that Cu and Mg were not present in this example.

EXAMPLE 5 In this example the procedure of Example 3 was employed with the following exceptions; no iron was present, agitation time was 24 hours after which reflectance was measured, the solvent system employed was perchloroethylene and the diketones used in place of acetylacetone are as indicated in Table IV, below. Cotton swatches were used.

As previously noted a quantity of from about .01 to 3 parts by weight of a lower alkanedione or cycloalkanedione is dissolved in parts by weight of a dry cleaning solvent system to provide a new composition of the present invention. This solvent system, as stated before, comprises essentially a halogenated organic dry cleaning solvent base well known to the art. In addition there may be present relatively small amounts of other additives such as soaps or detergents, water, brighteners, anti-static agents, etc. While these relatively small amounts of additives have no marked effect on the formation of the diketone-metal complexes, each plays a role in improving or providing other desirable features in a dry cleaning process. The new compositions of the present invention, which consist essentially of a major amount of dry cleaning solvent and a minor amount of vent contains an agent which prevents the deposition of metallic ions upon the material being cleaned, said agent being a diketone selected from the group consisting of acetylacetone, 2,3-butanedione, 2,4-pentanedione, 2,5-hexanedione, and 5,5-dimethyl-1,3-cycloheX- anedione, said agent being present in an amount of from 0.01 to 3 weight percent.

2. The method of claim 1 wherein said diketone acetylacetone.

3. The method of claim 1 wherein said diketone 5,5-dimethyl-1,3-cyclohexanedione.

4. The method of claim 1 wherein said diketone 2,3-butanedione.

5. The method of claim 1 wherein said diketone is 2,4-pentanedione.

6. The method of claim 1 wherein said diketone 2,5-hexanedione.

7. The method of claim 2 wherein said halogenated dry cleaning solvent consists essentially of perchloroethylene.

8. The method of claim 2 wherein said halogenated dry cleaning solvent is perchloroethylene containing a petroleum sulfonate base dry cleaning detergent.

9. The method of claim 2 wherein said halogenated dry cleaning solvent is perchloroethylene containing a phosphate base dry cleaning detergent.

10. In the method of cleaning fibrous materials in a halogenated dry cleaning solvent system the improvement which comprises employing a chlorinated hydrocarbon dry cleaning solvent containing from about 0.01 to 3 weight percent of a diketone selected from the group consisting of acetylacetone, 2,3-butanedione, 2,4-pentanedione, 2,5-hexanedione and 5,5-dimethyl-1,3-cyclohexanedione.

References Cited UNITED STATES PATENTS 1,911,289 5/1933 Reddish 252161 2,388,962 11/1945 Flett 252161 2,476,554 7/1949 Lincoln et al. 252171 XR 2,517,895 8/1950 Larcher et al. 252-171 3,117,152 1/1964 Michaels 252-171 LEON D. ROSDOL, Primary Examiner.

I T. FEDIGAN, Assistant Examiner. 

1. IN A METHOD OF CLEANING FIBROUS MATERIALS IN A DRY CLEANING SOLVENT BY CONTACTING THE MATERIAL WITH SAID DRY CLEANING SOLVENT, THE IMPROVEMENT WHEREIN THE SOLVENT CONTAINS AN AGENT WHICH PREVENTS THE DEPOSITION OF METALLIC IONS UPON THE MATERIAL BEING CLEANED, SAID AGENT BEING A DIKETONE SELECTED FROM THE GROUP CONSISTING OF ACETYLACETONE, 2,3-BUTANEDIONE, 2,4-PENTANEDIONE, 2,5-HEXANEDIONE, AND 5,5-DIMETHYL-1,3-CYCLOHEXANEDIONE, SAID AGENT BEING PRESENT IN AN AMOUNT OF FROM 0.01 TO 3 WEIGHT PERCENT. 